This invention relates to an image data conversion processing device for converting into television signals image data which are developed in plural kinds of developing formats in a memory, and an information processing device having the image data conversion processing device.
The information processing device comprises a personal computer including a memory and a processing unit, for example. The information processing device is connected to a cathode ray tube (CRT), and image data output from the memory is displayed on the CRT. At this time, the image data is developed in various kinds of developing formats into a video random access memory (VRAM).
The image data comprises 320 pixel (dots) on each line, and the total number of lines is 200. Alternately, the image data comprises 640 dotsxc3x97400 lines or 640 dotsxc3x97480 lines. The frame (screen) of the CRT is divided into a display frame area for displaying the image data and a non-display frame area.
A program has mode data corresponding to an image mode of the image data for displaying the image data on the screen. The mode data represents the size of the non-display frame area, the number of dots of the display frame area in a horizontal direction, a flyback. period and a read-out frequency for each dot.
A device for controlling the CRT to display the image data serves to set a horizontal scanning frequency 31 KHz on the basis of the mode data of the program when the image data comprises 640 dotsxc3x97480 lines. This device reads out the image data at a read-out frequency 28 MHz from the VRAM in accordance with the set horizontal scanning frequency. The CRT displays the image data on the display frame area thereof on the basis of the mode data.
On the other hand, this device sets a horizontal scanning frequency of 15 KHz when the image data comprises 320 dotsxc3x97200 lines. In this case, the device reads out the image data at a read-out frequency of 21 MHz from the VRAM in accordance with the horizontal scanning frequency. Further, the device sets a horizontal scanning frequency of 24 KHz when the image data comprises 640 dotsxc3x97400 lines. In this case, the device reads out the image data at a read-out frequency of 25 MHz from the VRAM in accordance with this horizontal scanning frequency. Various CRTs are individually provided in accordance with image data which are developed in various kinds of developing formats.
As described above, the device for controlling the CRT to perform its display operation enables the CRT to display image data corresponding to the image mode by setting a horizontal scanning frequency.
In addition, a multi-CRT capable of displaying various image data of 320 dotsxc3x97200 lines, 640 dotsxc3x97400 lines and 640 dotsxc3x97480 lines for example has been recently proposed. In this case, an information processing device having the program outputs a composite signal to the multi-CRT. The composite signal comprises horizontal synchronizing signal and a vertical synchronizing signal of 31/24/15. On the basis of the composite signal, the multi-CRT displays image data of RGB signals which are output from the information processing device.
On the other hand, there is a television device which is generally used for a domestic purpose in contraposition with the CRT and the multi-CRT as described above. The horizontal scanning frequency of this television device is specified to 15 KHz (accurately 15.73426 KHz), and an effective line number is specified to 400 lines. In the television device, one frame is displayed with two fields through an interlaced scanning operation in which the frame is scanned with interlacing lines.
It has been increasingly required that this type of television device is connected to the information processing device to promote the propagation of the information processing device. In this case, a scan converter for converting image data into a television signal is required. The scan converter is provided with a change-over switch for selecting any one of the plural horizonal scanning frequencies as described above, and on the basis of a set (selected) horizontal scanning frequency the scan converter converts the image data to be displayed by the information processing device. The television device displays an image on the frame thereof on the basis of the television signal.
As described above, when the television device is connected to the information processing device, the scan converter converts image data transmitted in an analog form into digital signals and then stores the digital signals into an internal VRAM. Further, the scan converter converts the image data to television signals which will be interlaced at a horizontal scanning frequency 15 KHz, and output the converted television signals to the television device.
When the line number of image data to be developed in the VRAM exceeds 400 lines of a television frame, the conventional scan converter displays only an image portion corresponding to 400 lines, which is specified by an adjusting volume. Therefore, in this case, a problem occurs in that the other image data corresponding plural lines other than the above 400 lines is not displayed on the television frame (screen). In order to solve this problem, the image data is compressed by the scan converter.
If the image data is uniformly compressed by the scan converter, an image which should not be compressed might be compressed. For example, the information processing device frequently outputs image data of 640 dotsxc3x97480 lines and image data of 640 dotsxc3x97420 lines at a horizontal scanning frequency 31 KHz, for example. In this case, the image data of 640 dotsxc3x97420 lines can be displayed on the television screen, whereas the image data of 640 dotsxc3x97480 lines can not be displayed on the television screen.
The scan converter serves to compress the image data of 640 dotsxc3x97480 lines to 640 dotsxc3x97420 lines at a constant compression rate, however, it also compresses, at the constant compression rate, the image data of 640 dotsxc3x97420 lines which is originally unnecessary to be compressed.
Further, use of the scan converter as described above induces a problem that a user must select a horizontal scanning frequency through the change-over switch. The composite signal may be used to remove a user""s manipulation of the change-over switch. The composite signal is a synchronizing signal, and comprises signals having respective frequencies. In this case, code information representing each of the frequencies is not transmitted, thus the frequency can not be immediately identified on the basis of the composite signal. Accordingly, for example, a frequency detector for detecting each frequency is provided to the scan converter. The manipulating operation of the change-over switch can be omitted by using a detection result of the frequency detector. However, in this case the circuit construction of the scan converter is more complicated.
Further, when the scan converter is used, the image data to be displayed, which is developed in the information processing device, is converted from a digital signal to an analog signal, then the analog signal is re-converted to the digital signal again by the scan converter. As a result, a problem occurs in that the image quality of the image data to be displayed on the television device is deteriorated.
Still further, in the conventional scan converter, the image data transmitted from the information processing device is converted to the television signal merely through the interlaced scanning operation. Therefore, a flicker occurs on the screen of the television device, and consequently a displayed image is obscure.
An object of this invention is to provided an image data conversion processing device capable of automatically generating television signals, having excellent display performance, on the basis of various kinds of image data to be developed on a VRAM having a single hardware construction, and an information processing device having the image data conversion processing device thus constructed.
In order to attain the above object, the image data converting device according to this invention converts image data of plural lines, which are stored in a storing unit and which can be developed in various kinds of developing formats, into television signals having a predetermined number of lines. The image data converting device includes an issue unit, plural line storing unit and a generating unit. The issue unit serves to issue an image data transmitting instruction to the storing unit in accordance with a period which is specified by a ratio of the line number of image data to be converted and a predetermined line number of the television signal.
The plural line storing units serve to cyclically store line by line, the image data transmitted from the storing unit on the basis of the transmission instruction of the issue unit.
The generating unit serves to multiply the image data stored in the line storing units by an interpolative coefficient corresponding to a developing format of an image data to be developed in plural interpolative coefficients which are set beforehand in correspondence with plural kinds of developing formats, in synchronism with the horizontal synchronizing signal of the television signal, thereby generating the television signal.
According to this invention, the image data of various kinds of developing formats can be automatically converted to the television signals.
Further, the image data conversion processing device according to this invention converts image data, which are stored in a storing unit and can be developed in plural kinds of developing formats, into a television signal having a predetermined line number. The image data comprises plural lines.
The image data conversion processing device of this invention includes a mode managing unit and a conversion processing unit. The mode managing unit serves to manage mode data corresponding to the line number of the image data.
The conversion processing unit serves to renew the conversion of the image data in accordance with the mode data supplied from the mode managing unit to convert the image data corresponding to at least plural mode data, to television signals.
Still further, the information processing device according to this invention, executes plural programs corresponding to different image modes. The image data includes a predetermined image mode. The program includes mode data having information for the image mode of the image data thereof or a specified information.
The information processing device executes the plural programs and has a processing unit for processing the mode data and the image data. The processing unit includes an image storing unit and a conversion processing unit. The image storing unit serves to store the program containing the mode data and the image data. The conversion processing unit converts the image data stored in the image storing unit according to a predetermined conversion in accordance with the mode data to thereby convert the image data to the television signal.
Still further, the image data conversion processing device according to this invention converts the image data, which can be developed in the plural kinds of developing formats, to a television signal of a predetermined line number. The image data comprises plural lines. The image data conversion processing device includes an even storing unit, an odd storing unit, a signal generating unit and a format conversion processing unit.
The even storing unit serves to store image data of even lines in the image data to be converted while the odd storing unit serves to store image data of odd lines in the image data to be converted.
The signal generating unit generates a horizontal synchronizing signal for the television signal, and also generates plural rate data which are determined by a ratio of the line number of the image data and the predetermined line number of the television signal in correspondence with the plural kinds of developing formats.
The format conversion processing unit serves to convert the image data of the even and odd lines supplied from the even storing unit and the odd storing unit into the format of the television signal using the horizontal synchronizing signal and the rate data corresponding to the developing format of the image data to be converted.
According to the information processing device of this invention, the even storing unit and the odd storing unit are provided and a calculation is carried out by reading out the image data of the even and odd lines, so that the construction of the format conversion processing unit can be simplified.
Still further, the information processing device of this invention converts the image data, which are stored in a storing unit, to a television signal having a predetermined line number. The image data comprises plural lines.
One frame of the television signal comprises plural fields. The information processing device of this invention includes a linear interpolating unit, plural field storing units, a synchronizing signal generating unit and a field control unit.
The linear interpolating unit serves to linearly interpolate image data of two lines of an image data line supplied from the storing unit and an image data line adjacent to the above image data line using a predetermined interpolative coefficient, thereby generating the television signal.
The plural field storing units are provided at the input or output side of the linear interpolating unit to store the respective lines on a field basis. The synchronizing signal generating unit serves to generate the horizonal synchronizing signal and the vertical synchronizing signal of the television signal.
The field control unit serves to perform write-in and read-out operations of the image data field by field for the plural field storing units on the basis of the synchronizing signal which is generated in the synchronizing signal generating unit.
According to the information processing device of this invention, the image data is subjected to the processing field by field to generate the television signal.
As described above, according to the image data conversion processing device and the information processing device of this invention, the television signal having excellent display performance can be automatically generated from the image data of various kinds of developing format but still keeping a single hardware construction, thus manipulation by the user can be removed.